linux-kernel - Re: [PATCH v4 0/6] KVM: x86/vPMU: Efficiency optimization by reusing last created perf

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Message-ID: <21372ed6-b8c1-3609-1ab8-2d566a4319e6@redhat.com>
Date:   Tue, 12 Nov 2019 11:09:15 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Like Xu <like.xu@...ux.intel.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: Re: [PATCH v4 0/6] KVM: x86/vPMU: Efficiency optimization by reusing
 last created perf_event

On 12/11/19 07:08, Like Xu wrote:
> 
> For vPMU, please review two more patches as well:
> +
> https://lore.kernel.org/kvm/20191030164418.2957-1-like.xu@linux.intel.com/
> (kvm)

If I understand this patch correctly, you are patching the CPUID values
passed to the KVM_SET_CPUID2 ioctl if they are not valid for the host.
Generally we don't do that, if there is garbage in CPUID the behavior of
the guest will be unreliable.

Paolo